Probability and Statistics — Answer Key
Part A: Fill in the Blank
Write the missing word or number on each line.
1. A tree diagram for flipping 2 coins lists outcomes HH, HT, TH, TT.
The four equally likely outcomes are HH, HT, TH, and TT.
2. P(no heads) when flipping 2 coins = 1/4.
One outcome (TT) out of 4 has no heads, giving 1/4.
3. P(exactly one head) when flipping 2 coins = 1/2.
2 favorable outcomes (HT, TH) out of 4 simplify to 1/2.
4. In the set 10, 12, 14, 16, 100, the outlier is 100.
100 is much larger than 10 through 16, making it the outlier.
5. After removing 100 from 10, 12, 14, 16, 100, the new mean is 13.
Sum is 52, and 52 divided by 4 equals 13, the new mean.
6. The median of 10, 12, 14, 16, 100 is 14.
With five values, the third one (14) is the median, barely affected by the outlier.
7. P(both tails) on 2 fair coins = 1/4.
One favorable outcome (TT) out of 4 equally likely outcomes is 1/4.
8. A line plot shows fractional measurements of length feet such as 1/2, 1/4, 3/4.
Length values can be plotted as Xs above a number line in fractions of a foot.
9. A circle graph is best for showing parts of a whole using a circle.
Circle (pie) graphs split a whole into parts so you see each portion of 100%.
Part B: Matching
Match each item on the left to the correct answer on the right.
1. Match each item to its correct answer.
Outcomes of 2 coin flips
→ HH, HT, TH, TT
HH, HT, TH, TT
P(both heads)
→ 1/4
1/4
Outlier in 5,6,7,90
→ 90
90
Display for parts of a whole
→ Circle graph
Circle graph
Two coins have 4 outcomes; HH is 1 of 4; 90 is far from 5-7; circle graphs show parts of a whole.